/*
 *  Copyright 2007-2008 by Matthias Buch-Kromann <mbk.isv@cbs.dk>.
 *  *
 *  This file is part of the Open-source Dependency Toolkit (OSDT),
 *  see http://code.google.com/p/open-source-dependency-toolkit.
 *  
 *  The OSDT is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as 
 *  published by the Free Software Foundation, either version 3 of 
 *  the License, or (at your option) any later version.
 * 
 *  The OSDT is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 * 
 *  You should have received a copy of the GNU Lesser General Public 
 *  License along with the OSDT in the files COPYING and COPYING.LESSER.
 *  If not, see http://www.gnu.org/licenses.
 */

package org.osdtsystem.functions;

import org.osdtsystem.graphs.GraphAccessor;

/**
 *
 * @author Matthias Buch-Kromann <mbk.isv@cbs.dk>
 */
public class FuncForallExists<V> extends AbstractSingletonFunction<Boolean> {
    Function<? extends V> generator;
    SingletonFunction<Boolean> condition;
    String var;
    Boolean forall;
    
    public FuncForallExists(FuncVariable<V> var, Function<? extends V> generator,
            SingletonFunction<Boolean> condition, boolean forall) {
        super(generator, condition);
        this.generator = generator;
        this.condition = condition;
        this.forall = forall;
        this.var = var.unaryVariable();
        addLocalBoundVariable(this.var);
    }
    
    @Override
    public Boolean _singletonFunctionValue(LocalFunction<?, ?> caller, FunctionContext context,
            GraphAccessor accessor) {
        for (V arg : generator.functionValue(caller, context, accessor)) {
            // Save state and set variable
            int state = context.state();
            context.pushVariable(var, arg);
            
            // Add node if it satisfies condition
            if (forall ^ condition.singletonFunctionValue(caller, context, accessor))
                return forall ? Boolean.FALSE : Boolean.TRUE;
            
            // Restore state
            context.restoreState(state);
        }
        
        // Return nodes
        return forall ? Boolean.TRUE : Boolean.FALSE;
    }

    @Override
    void toStringBuilder(FunctionStringBuilder builder) {
        builder.addParameter("type", forall ? "ALL" : "EXISTS");
        builder.addParameter("var", var);
        builder.addSubfunction("gen", generator);
        builder.addSubfunction("cond", condition);
    }
}
